Electric circuit device, electric circuit module, and power converter

ABSTRACT

The present invention provides an electric circuit device in which it is possible to achieve simultaneously the improvement of cooling performance and reduction in operating loss due to line inductance. The above object can be attained by constructing multiple plate-like conductors so that each of these conductors electrically connected to multiple semiconductor chips is also thermally connected to both chip surfaces of each such semiconductor chip to release heat from the chip surfaces of each semiconductor chip, and so that among the above conductors, a DC positive-polarity plate-like conductor and a DC negative-polarity plate-like conductor are opposed to each other at the respective conductor surfaces.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/740,622, filed Apr. 26, 2007 which claims the benefit of priorityunder 35 U.S.C. §119 to Japanese patent application serial no.2006-123835, filed Apr. 27, 2006, the disclosure of which isincorporated herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electric circuit device adapted toconfigure an electric circuit that uses semiconductors, an electriccircuit module with the device mounted therein, and an electric powerconverter having the module.

2. Description of the Related Art

Known techniques related to an electric circuit device adapted toconfigure an electric circuit that uses semiconductors, an electriccircuit module having the device mounted therein, and an electric powerconverter having the module, are described in JP-A-2004-208411,JP-A-2004-193476, and JP-A-10-248266, for example. JP-A-2004-208411discloses the technique for sandwiching high-side semiconductor chips(IGBT chip and diode chip) and low-side semiconductor chips (IGBT chipand diode chip) by use of a common middle-side plate and high-side plateand a common middle-side plate and low-side plate, respectively, andcooling each of the semiconductor chips from both sides.

Also, JP-A-2004-193476 discloses the technique for arranging an IGBTelement and a diode element between a P-side electrode, a middleelectrode, and an N-side electrode, and stacking these elements in alongitudinal direction for reduced line inductance.

Additionally, JP-A-10-248266 discloses the technique for arranging asemiconductor module and a smoothing capacitor vertically, electricallyconnecting these elements via two pairs of connection conductors thatare a stacked structure of thin plates each fastened at one end to theterminal sections of the module and the capacitor, connected at theother end to each other with the same polarity, and formed with aninsulating member sandwiched between heteropolar conductors, andshortening a line distance between the module and the capacitor in orderto reduce line inductance therebetween.

SUMMARY OF THE INVENTION

In recent years, development of electric driving has been accelerated invarious industries. In automobiles, for example, electric driving invarious systems for installation in the vehicle, including a vehiculardriving system, is increasing in terms of improvement of the vehicle infuel efficiency and protection of the global environment. Furtheracceleration of such electric driving is recently desired. Toelectrically drive a vehicle-mounted system, however, it becomesnecessary to add an electric machine that drives a mechanism to bedriven, and an electric power converter that controls driving of arotary electric machine by controlling the electric power supplied froma vehicle-mounted power supply to the rotary electric machine, as wellas to adopt substitutes for the conventional system components. Forfurther accelerated electric driving of the vehicle-mounted system,therefore, the electric machine and its controller require furtherimprovement in mountability and further reduction in price.

The electric machine and the electric power converter must be furtherminiaturized to implement their further improvement in mountability andtheir further reduction in price. One possible method of achievingfurther miniaturization of the power converter is to construct anelectric circuit device by use of smaller semiconductor chips to form apower conversion circuit and then mount the electric circuit device in amore compact electric circuit module. However, semiconductor chipsgenerate a large amount of heat during an electrical conducting state,and as the chips are dimensionally reduced, they correspondinglyincrease in heat capacity and hence in the amount of heat generated. Theamount of heat generated by the semiconductor chips is also increased bythe internal line inductance of the electric circuit device and byelectrical loss due to the line inductance occurring at the input sideof the electric circuit device during operation. Accordingly, furtherimprovement of the electric circuit device in cooling performance andfurther reduction of the operating loss due to the line inductancebecome important technical factors in miniaturizing the power converter.

In particular, to miniaturize the power converter exposed to a severeoperating/mounting environment, for example, to miniaturize the powerconverter used in the driving system of an automobile, it is absolutelynecessary to simultaneously realize further improvement of the electriccircuit device in cooling performance and further reduction of theoperating loss due to the line inductance.

In this context, as disclosed in the three JP-A publications, theeffectiveness of the conventional techniques is confined only to eitherthe improvement of the electric circuit device in terms of coolingperformance or the reduction of the operating loss due to the lineinductance. At present, therefore, the conventional techniques are notas effective as they can attain both of the above two factors.

The present invention typically provides an electric circuit device thatcan attain improvement of its cooling performance and reduction of itsoperating loss due to line inductance.

In the electric circuit device of the present invention, a plurality ofplate-shaped conductors electrically connected to a plurality ofsemiconductor chips are typically constructed so that each plate-shapedconductor is thermally connected to both sides of each semiconductorchip in order to make it possible to release heat from both chipsurfaces of each semiconductor chip via the plate-shaped conductor. Theplate-shaped conductors are also typically constructed so that among themultiple plate-shaped conductors, only a plate-shaped conductor for DCpositive polarity and a plate-shaped conductor for DC negative polarityare opposed to each other at respective conductor surface.

According to the present invention having the above features, heatgenerated by each semiconductor chip can be released to the outside ofthe device via the plate-shaped conductors thermally connected to bothsides of the semiconductor chip, so the semiconductor chip itself can becooled from both sides thereof. In addition, according to the presentinvention, when currents of equal magnitude flow into the plate-shapedconductor for DC positive polarity and the plate-shaped conductor for DCnegative polarity, directions of the currents can be changed to oppositedirections at opposed sections of the two plate-shaped conductors. Thus,a magnetic field generated by the current flowing through theplate-shaped conductor for DC positive polarity can be offset by amagnetic field generated by the current flowing through the plate-shapedconductor for DC negative polarity. Hence, according to the presentinvention, the line inductance occurring in the electric circuit devicecan be reduced and this, in turn, makes it possible to reduce theoperating loss of the semiconductor due to line inductance. According tothe present invention, therefore, the improvement of cooling performanceand the reduction of the operating loss due to the line inductance canbe realized at the same time.

The present invention also provides an electric circuit module that usesan electrical insulating structure to mount the above electric circuitdevice on a heat release structure having a surface cooled by a coolingmedium.

In addition, the present invention provides an electric power converterthat includes the above electric circuit module, a controller forcontrolling an operational state of the electric circuit module, and acapacitor device electrically connected to an electric power conversioncircuit composed of the electric circuit module.

According to the present invention summarized above, since theimprovement of cooling performance and the reduction of the operatingloss due to line inductance can be realized at the same time, a morecompact electric circuit device can be constructed using smallersemiconductor chips.

According to the present invention, since the above electric circuitdevice is mounted, it is also possible to construct a more compactelectric circuit module.

In addition, according to the present invention, since the aboveelectric circuit module is mounted, it is possible to construct a morecompact electric power converter and thus to contribute to improving thepower converter in mountability and reducing a price of the powerconverter. The present invention yields advantageous effectsparticularly significant in the power converter mounted in anautomobile.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing an internal configurationof an electric circuit device according to a first embodiment of thepresent invention;

FIG. 2 is an assembly perspective view of FIG. 1;

FIG. 3 is a perspective view showing an external configuration of theelectric circuit device according to the first embodiment of the presentinvention;

FIG. 4 is a cross-sectional view taken along the line A-A′ of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line A-B′ of FIG. 3;

FIG. 6 is a circuit diagram that shows advantageous effects of theelectric circuit device according to the first embodiment of the presentinvention;

FIG. 7 is a perspective view that shows advantageous effects of theelectric circuit device according to the first embodiment of the presentinvention;

FIG. 8 is a perspective view showing an inverter configuration accordingto the first embodiment of the present invention;

FIG. 9 is a cross-sectional view taken along the line A-A′ of FIG. 8;

FIG. 10 is an exploded perspective view of FIG. 8;

FIG. 11 is a cross-sectional view taken along the line A-A′ of FIG. 10;

FIG. 12 is another exploded perspective view of FIG. 8;

FIG. 13 is a cross-sectional view taken along the line A-A′ of FIG. 12;

FIG. 14 is a plan view showing a configuration of a heat release baseused in the inverter of FIG. 8;

FIG. 15 is a perspective view showing a configuration of a connectionmember used in the inverter of FIG. 8;

FIG. 16 is a side view showing the configuration of the connectionmember used in the inverter of FIG. 8;

FIG. 17 is a top view showing the configuration of the connection memberused in the inverter of FIG. 8;

FIG. 18 is a cross-sectional view showing the configuration of theconnection member used in the inverter of FIG. 8;

FIG. 19 is a circuit diagram showing a circuit configuration of theinverter according to the first embodiment of the present invention;

FIG. 20 is a block diagram showing a hybrid automobile configurationaccording to the first embodiment of the present invention;

FIG. 21 is a perspective view showing a configuration of an electriccircuit device according to a second embodiment of the presentinvention;

FIG. 22 is a perspective view showing a configuration of an electriccircuit device according to a third embodiment of the present invention;

FIG. 23 is a perspective view showing a configuration of an electriccircuit device according to a fourth embodiment of the presentinvention;

FIG. 24 is a perspective view showing a configuration of an inverteraccording to a fifth embodiment of the present invention;

FIG. 25 is an exploded perspective view of FIG. 24;

FIG. 26 is an exploded perspective view showing a configuration of anintegrated terminal used in the inverter of FIG. 24;

FIG. 27 is a perspective view showing a configuration of an inverteraccording to a sixth embodiment of the present invention;

FIG. 28 is an exploded view of FIG. 27;

FIG. 29 is an exploded perspective view showing a configuration of anelectric circuit device according to a seventh embodiment of the presentinvention;

FIG. 30 is a perspective view showing an external configuration of theelectric circuit device according to the seventh embodiment of thepresent invention;

FIG. 31 is an exploded perspective view showing an inverterconfiguration according to the seventh embodiment of the presentinvention;

FIG. 32 is a cross-sectional view taken along the line A-A′ of FIG. 31;

FIG. 33 is an exploded perspective view showing another configuration ofthe electric circuit device according to the seventh embodiment of thepresent invention;

FIG. 34 is an exploded perspective view showing a configuration of anelectric circuit device according to an eighth embodiment of the presentinvention; and

FIG. 35 is a cross-sectional view showing the configuration of theelectric circuit device according to the eighth embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described hereunder inaccordance with the accompanying drawings.

Examples of applying the present invention to a vehicular electric powerconverter of a vehicular electric machine system mounted in anautomobile, and more particularly, to a vehicular driving inverter usedin a vehicular electric machine system and exposed to very severeenvironments such as a mounting environment and an operatingenvironment, will be described hereunder as the embodiments below. Thevehicular electric power inverter disposed in an vehicular electricmachine system as a controller to control driving of a vehicular drivingmotor transforms DC power supplied from a vehicle-mounted battery orvehicle-mounted power generator constituting a vehicle-mounted powersupply, into required AC power and then supplies the AC power to thevehicular driving motor to control the driving thereof.

The configuration described below can also be applied to invertersconstructed for purposes other than vehicle driving, for example, aninverter used as a controller of an electric braking device or electricpower steering device. In addition, the configuration below can beapplied to DC-DC power converters such as a DC-DC converter and a DCchopper, to AC-DC power converters, or to other vehicular powerconverters. Furthermore, the configuration below can be applied toindustrial power converters used as controllers of motors which drivefactory equipment, or to household power converters used in controllersof motors which drive household solar light power-generating systems orelectrical household appliances. For improved mountability and reducedprice of an electric power converter, application to a more compactconverter, in particular, is preferable.

Also, the embodiments below will be described hereunder taking anexample in which a vehicular driving electric machine system with avehicular driving inverter applying the present invention is mounted ina hybrid automobile that employs an internal-combustion engine and avehicular driving motor as driving sources of a vehicle and isconstructed so as to drive either one of two pairs of front or rearwheels of the vehicle. Some kinds of hybrid automobiles use an engine todrive either one of two pairs of front or rear wheels and a vehiculardriving motor to drive the other pair of front or rear wheels. Thevehicular driving electric machine system in any one of the embodimentscan also be applied to the hybrid automobile constructed in that way.

The vehicular driving electric machine system can be further applied toa pure electric automobile constructed so as to drive either front orrear wheels by using a vehicular driving motor as a driving source ofthe vehicle. Furthermore, the vehicular electric machine system with thevehicular inverter applying the present invention can be applied to asimplified hybrid automobile adapted to use an internal-combustionengine as a driving source of the vehicle to drive either the front orrear wheels and use the vehicular electric machine system to start theengine or to provide engine power assistance for the engine start andfor accelerated engine operation. Moreover, the vehicular electricmachine system with the vehicular inverter applying the presentinvention can be applied to an automobile adapted to use aninternal-combustion engine as a driving source of the vehicle to driveeither the front or rear wheels and to have a vehicle-mounted electricmachine system such as an electric braking device and an electric powersteering device.

First Embodiment

Hereunder, a first embodiment of the present invention will be describedin accordance with FIGS. 1 to 20.

First, a configuration of a hybrid electric automobile 1 is describedbelow using FIG. 20.

The hybrid electric automobile (hereinafter, referred to as HEV) 1 ofthe present embodiment is one electric vehicle and has two vehiculardriving systems. One of them is an engine system that uses aninternal-combustion engine 10 as a motive power source. The enginesystem is used as a driving source of the HEV. The other is a vehicularelectric machine system that use motor generators 30, 40 as motive powersources. The vehicular electric machine system is primarily used asanother driving source of the HEV and as an electric power generator forthe HEV.

At a front section of a vehicle body (not shown), front wheel axles 3are axially supported so as to be rotatable. One pair of front wheels 2are disposed at both ends of each front wheel axle 3. At a rear sectionof the vehicle body, rear wheel axles (not shown) are axially supportedso as to be rotatable. One pair of rear wheels (not shown) are disposedat both ends of each rear wheel axle. The HEV of the present embodimentemploys a so-called front wheel drive scheme. In this scheme, the frontwheels 2 operate as main wheels driven by motive power, and the rearwheels operate as trailing wheels simultaneously rotated by movements ofthe front wheels 2. The HEV, however, may employ the inverse of theabove, that is, a rear wheel drive scheme.

A front wheel differential gear 4 (hereinafter, referred to as a frontwheel DEF) is provided centrally between the front wheel axles 3. Thefront wheel axles 3 are mechanically connected to an output side of thefront wheel DEF 4. A transmission 20 is mechanically connected at itsoutput shaft to an input side of the front wheel DEF 4. The front wheelDEF 4 is a differential motive power distributor that distributesrotational driving force to the left and right front wheel axles 3 afterthe rotational driving force has been transmitted from the transmission20 as a result of a gearshift thereby. The motor generator 30 ismechanically connected at its output side to an input side of thetransmission 20. The engine 10 and the motor generator 40 aremechanically connected at respective output sides to an input side ofthe motor generator 30 via the motive power distributor 50.

The motor generators 30, 40 and the motive power distributor 50 arestored within an enclosure of the transmission 20.

The motive power distributor 50 is a differential mechanism constitutedby gears 51 to 58. The gears 53 to 56 are bevel gears. The gears 51, 52,57, 58 are spur gears. Motive power of the motor generator 30 istransmitted directly to the transmission 20. A shaft of the motorgenerator 30 is coaxial with the gear 57. In this configuration, whenelectric power for driving is not supplied to the motor generator 30,motive power that has been transmitted to the gear 57 is furthertransmitted intact to the input side of the transmission 20. When thegear 51 is driven by operation of the engine 10, motive power of theengine 10 is transmitted from the gear 51 to the gear 52, then from thegear 52 to the gears 54 and 56, and from the gears 54 and 56 to the gear58. Finally, the power is transmitted to the gear 57. When the gear 53is driven by operation of the motor generator 40, rotation of the motorgenerator 40 is transmitted first from the gear 53 to the gears 54 and56, and then from the gears 54 and 56 to the gear 58. Finally, therotation is transmitted to the gear 57.

Instead of the above differential mechanism, an epicyclic gear train orany other appropriate mechanism may be used as the motive powerdistributor 50.

The motor generator 30 (40) is a synchronous machine having a permanentmagnet in a rotor section. Alternating-current power supplied to anarmature winding assembly 31 (41) of a stator is controlled by aninverter 100 (300), whereby driving is controlled. A battery 60 iselectrically connected to the inverter 100 (300), and electric power canbe exchanged reciprocally between the battery 60 and the inverter 100(300).

The present embodiment includes a first motor electric power generatorunit consisting essentially of the motor generator 30 and the inverter100, and a second motor electric power generator unit consistingessentially of the motor generator 40 and the inverter 300, and eitherof the two motor electric power generator units is selectively usedaccording to a particular operating state. That is to say, for vehicledrive torque assistance during vehicle driving by the motive powertransmitted from the engine 10, the second motor electric powergenerator unit is activated as an electric power generator unit togenerate electric power using the motive power of the engine 10, and theelectric power that has thus been obtained operates the first motorelectric power generator unit as an electric driving unit. In addition,for vehicle speed assistance in a case similar to the above, the firstmotor electric power generator unit is activated as an electric powergenerator unit to generate electric power using the motive power of theengine 10, and the electric power that has thus been obtained operatesthe second motor electric power generator unit as the electric drivingunit.

Additionally, in the present embodiment, operating the first motorelectric power generator unit as the electric driving unit by the powerof the battery 60 makes the vehicle drivable only by the motive power ofthe motor generator 30.

Furthermore, in the present embodiment, the battery 60 can be rechargedusing electric power generated by operating the first motor electricpower generator unit or the second motor electric power generator unitas the electric power generator unit by use of the motive power of theengine 10 or the motive power transmitted from the wheels.

Next, electric circuit configurations of the inverters 100, 300 will bedescribed hereunder using FIG. 19.

While the present embodiment is described below using an example ofconstructing the inverters 100, 300 independently, the inverters 100,300 may be integrated to construct one inverter unit.

In addition, in the present embodiment, an electric power system and asignal system are shown with a solid line and a dotted line,respectively, to make the electric power system and the signal systemreadily distinguishable.

The inverter 100 (300) includes a semiconductor module 101, a capacitor102, and a controller 103.

The semiconductor module 101 constitutes a main circuit for electricpower conversion and has a plurality of switching power semiconductorelements. The plurality of switching power semiconductor elementsoperate under a driving signal output from the controller 103, andconvert the DC power supplied from the battery 60, into three-phase ACpower. The thus-converted power is supplied to the armature windingassembly 31 (41) of the motor generator 30 (40). The main circuit forelectric power conversion is composed of a three-phase bridge circuit,and series circuits for three phases are each formed by electricalconnection between a positive side and negative side of the battery 60.The series circuits are also called arms, which are constructed of theswitching power semiconductor element for an upper arm and the switchingpower semiconductor element for a lower arm.

The present embodiment uses insulated gate bipolar transistors (IGBTs)111 as the switching power semiconductor elements. Each IGBT 111 has acollector electrode, an emitter electrode, and a gate electrode. A diode112 is electrically connected between the collector electrode andemitter electrode of the IGBT 111. The diode 112 has a cathodicelectrode and an anodic electrode, and the cathodic electrode and theanodic electrode are electrically connected to the collector electrodeand emitter electrode, respectively, of the IGBT 111 so that a directionin which a current flows from the emitter electrode of the IGBT 111towards the collector electrode thereof becomes a forward direction.

Metal-oxide semiconductor field effect transistors (MOSFETs) may be usedas the switching power semiconductor elements. Each MOSFET has a drainelectrode, a source electrode, and a gate electrode.

Between its source electrode and its drain electrode, the MOSFETincludes a parasitic diode adapted so that a direction in which acurrent flows from the drain electrode towards the source electrodebecomes a forward direction. Accordingly, unlike an IGBT, there is noneed to provide an independent diode.

Arms for three phases are provided in association with phase windings ofthe armature winding assembly 31 (41) in the motor generator 30 (40).The source electrode of the IGBT 111 and the drain electrode thereof areelectrically interconnected in series via an intermediate electrode 120,whereby each of the arms is constructed. The drain electrode of the IGBT111 in the upper arm of the arms is electrically connected to apositive-polarity capacitor electrode 171 of the capacitor device 102via a positive-polarity electrode 130, and the source electrode of theIGBT 111 in the lower arm of the three arms is electrically connected toa negative-polarity capacitor electrode 172 of the capacitor device 102via a negative-polarity electrode 140. The intermediate electrode 120equivalent to a midpoint section between the three arms (i.e., aconnection between the source electrode of the IGBT 111 in the upper armand the drain electrode of the IGBT 111 in the lower arm) iselectrically connected to the appropriate phase winding of the armaturewinding assembly 31 (41) in the motor generator 30 (40). In the presentembodiment, as will be detailed later herein, one arm is constructedusing one electric circuit device (semiconductor device) 110.

The capacitor device 102 constitutes a smoothing circuit that suppresseschanges in DC voltage due to switching operation of the IGBT 111. Apositive-polarity side and negative-polarity side of the battery 60 areelectrically connected to the positive-polarity capacitor electrode 171and negative-polarity capacitor electrode 171 of the capacitor device102, respectively. Thus, between a DC side (input side) of thesemiconductor module 101 and the battery 60, the capacitor device 102 iselectrically connected in parallel to both the DC side of thesemiconductor module 101 (i.e., between the respective positive-polarityelectrodes 130 and negative-polarity electrodes 140 of the three arms)and the battery 60.

The controller 103 for operating the IGBT 111 includes a control unitthat uses input information from other controllers or sensors or otherelements to create a timing signal in order to control switching timingof the IGBT 111, and a driver that uses an output timing signal from thecontrol unit to create a driving signal required for the IGBT 111 toperform switching operation.

The control unit is constituted by a microcomputer. A target torquevalue requested to the motor generator 30 (40), a value of the electriccurrent supplied from the semiconductor module 101 to the armaturewinding assembly 31 (41) of the motor generator 30 (40), and a magneticpole position of the rotor of the motor generator 30 (40) are input asinput information to the microcomputer. The target torque value is basedon a command signal that has been output from a host controller. Theelectric current value is a result of detection based on a detectionsignal output from a current sensor 194. The magnetic pole position is aresult of detection based on a detection signal output from a rotormagnetic pole sensor 32 (42) provided in the motor generator 30 (40). Anexample of detecting two phases of current data is described below inconnection with the present embodiment. However, three phases of currentdata may be detected instead.

The microcomputer uses the above target torque value to compute electriccurrent command data on a d-axis and a q-axis, uses differentialsbetween computed electric current command data of the d-axis and q-axisand detected electric current command data of the d-axis and q-axis tocompute voltage command data on the d-axis and the q-axis, and uses adetected magnetic pole position to convert computed voltage command dataof the d-axis and q-axis into voltage command data of each phase (U, V,W). Also, the microcomputer create a pulse-like modulated wave bycomparing a fundamental wave (sine wave) and a carrier wave (triangularwave) based on the voltage command data of the U-phase, V-phase, andW-phase, and outputs the modulated wave as a PWM (Pulse Width Modulated)signal to the driver. Six PWM signals, one for the upper or lower arm ofeach phase, are output from the microcomputer to the driver. Timingsignals output from the microcomputer may be other signals such asrectangular wave signals.

The driver is constituted by an integrated circuit, or an IC that is anintegrated set of multiple electronic circuit components. While thepresent embodiment is described below taking a one-in-one scheme as anexample of providing one IC for the upper or lower arm of each phase,the present invention may employ any other scheme such as a two-in-onescheme with one IC provided for the upper and lower arms of each phase,or a six-in-one scheme with one IC provided for all arms. To drive thelower arm, the driver amplifies an associated PWM signal and outputs thePWM signal as a driving signal to the gate electrode of the IGBT 111 ofthe lower arm. To drive the upper arm, the driver shifts a referencepotential level of an associated PWM signal to a reference potentiallevel of the upper arm before amplifying the PWM signal, and thenoutputs the PWM signal as a driving signal to the gate electrode of theIGBT 111 of the upper arm. Thus, each IGBT 111 performs the switchingoperation in accordance with the input driving signal.

The controller 103 also detects abnormal states (overcurrent,overvoltage, overtemperature, and the like), thus protecting thesemiconductor module 101. For this purpose, sensing information is inputto the controller 103. For example, information on the current flowingthrough the source electrode of each IGBT 111 is input from a sensorlead wire 163 of each arm to the associated driver (IC). Accordingly,the driver (IC) conducts overcurrent detection and if an overcurrent isdetected, the driver (IC) stops the switching operation of theassociated IGBT 111 and protects the associated IGBT 111 from theovercurrent. Temperature information on the semiconductor module 101 isinput from a temperature sensor 104 provided in/on the semiconductormodule 101, to the microcomputer. Voltage information on the DCpositive-polarity side of the semiconductor module 101 is also input tothe microcomputer. The microcomputer conducts overtemperature andovervoltage detection based on those kinds of information, and if anovertemperature or an overvoltage is detected, the microcomputer stopsthe switching operation of all IGBTs 111 and protects the semiconductormodule 101 from the overtemperature or the overvoltage.

Next, actual configurations of the inverters 100, 300 for realizing theelectric circuit configuration of FIG. 19 will be described hereunderusing FIGS. 1 to 18.

Under the conventional techniques, multiple semiconductor chips aremounted on the heat-releasing base of a module casing via anelectrically insulated circuit board, then wiring is conducted usingwiring members such as wires, and a semiconductor module is constructed.In the present embodiment, however, semiconductor chips and wiringmembers are constructed as components or devices beforehand in aseparated state with respect to the semiconductor module. Thus, aso-called discrete component construction or device construction isrealized and the semiconductor module is constructed by building thediscrete components or the devices into the semiconductor module duringmanufacture thereof.

First, a configuration of the electric circuit device (semiconductordevice) 110, one of the above discrete components or devices, will bedescribed hereunder using FIGS. 1 to 5.

In the present embodiment, as described above, the arms are constructedas discrete components or devices in two-in-one units.

The electric circuit device 110 is, in appearance, a structure formed asfollows. First, three kinds of elements (namely, the semiconductor chipsconstituting an IGBT 111 and a diode 112, metallic buffering members113, 114, and portions of multiple electrodes and multiple wires) arefirst embedded in a molded body 150 constructed by transfer-molding asealing resin (epoxy resin) that is a packaging material. Next, otherportions of the multiple electrodes and multiple wires are eitherextended outward from the inside of the molded body 150 to the outsidethereof, or exposed outside the molded body 150.

The electric circuit device 110 has the intermediate electrode 120, thepositive-polarity electrode 130, and the negative-polarity electrode140, as the above multiple electrodes. The intermediate electrode 120,the positive-polarity electrode 130, and the negative-polarity electrode140 are each formed using a flat-plate conductor made of a metal, forexample, a copper alloy or copper excellent in thermal conductivity andin electrical conductivity. The electric circuit device 110 has theforegoing gate lead wires 160, 162 and sensor lead wires 161, 163, asthe above multiple wires. The gate lead wires 160, 162 and the sensorlead wires 161, 163 are each formed using an elongated rod-like orpin-shaped prismatic conductor made of a metal, for example, a copperalloy or copper excellent in thermal conductivity and in electricalconductivity.

In the present embodiment, the intermediate electrode 120, thepositive-polarity electrode 130, and the negative-polarity electrode 140are constructed so that the semiconductor chips inside the electriccircuit device 110 can be improved in heat release characteristics andreduced in line inductance at the same time.

In the present embodiment, the intermediate electrode 120 is hereinafterreferred to simply as the M-electrode 120, the positive-polarityelectrode 130 as the P-electrode 130, and the negative-polarityelectrode 140 as the N-electrode 140, the gate lead wires 160, 162 asthe G-wires 160, 162, and the sensor lead wires 161, 163 as the S-wires161, 163.

Additionally, in the present embodiment, in a rectangular parallelepideor square plate body, one pair of rectangular opposed planes larger insurface area than other planes are defined as principal planes. Also,four rectangular planes of the rectangular parallelepide or square platebody that extend along, and are formed at right angles to, four edges(four sides) of each such principal plane, and that have surface areassmaller than those of the principal planes, are defined as peripheralplanes. In addition, one pair of longer sides of all four sides thatconstitute rectangular planes including the principal planes are definedas long sides, and one pair of shorter sides are defined as short sides.Furthermore, a direction in which the long sides of each rectangularplane including each principal plane extends is defined as a long-sidedirection or a longitudinal direction, and a direction in which theshort sides of the rectangular plane including the principal planeextends is defined as a short-side direction or a lateral direction.Moreover, a distance between the principal planes is defined asthickness or height, and an opposite direction to each principal plane(i.e., a direction in which the long sides of each peripheral planeextends) is defined as a thickness direction or a height direction.

The molded body 150 is subdivided into two molded bodies: a first moldedsection 151 and a second molded section 152.

The first molded section 151 is a rectangular parallelepide or squareplate section formed to package semiconductor chip-mounting sections ofthe M-electrode 120, P-electrode 130, and N-electrode 140, and topackage portions of the G-wires 160, 162, and S-wires 161, 163. Lengthof the first molded section 151 is greater than plate thicknesses of theabove electrodes or diameters of the above wires.

The second molded section 152 is formed centrally at one of lateraledges of the first molded section 151. The second molded section 152 isa polyhedral solid section for packaging respective bends of theP-electrode 130 and N-electrode 140, and is formed integrally with thefirst molded section 151. The polyhedral solid constituting the secondmolded section 152 is a cutout formed by cutting off a portion of therectangular parallelepide. That is to say, when the rectangularparallelepide is disposed so that one principal plane thereof faces thefirst molded section 151, this principal plane facing the first moldedsection 151 is formed into a stepped shape and a concave-like groove 153extending continuously in the long-side direction is formed centrally inthe short-side direction of the other principal plane of the rectangularparallelepide. The portion of the second molded section 152 that extendsin the same direction as that of the long sides of the first moldedsection 151 is dimensionally smaller than the long sides of the firstmolded section 151. The portion of the second molded section 152 thatextends in the same direction as thickness of the long sides of thefirst molded section 151 is dimensionally larger than thickness of thefirst molded section 151. The second molded section 152 is formed withtwo steps. One of the two steps forms a connection region with respectto one lateral peripheral planes of the first molded section 151, and ishigher than the other step. That is to say, one step is an upper stageand the other step is a lower stage.

The concave-like groove 153 formed at a second short side of the secondmolded section 152 is formed so as to engage with a convex-likeprotrusion provided on a connecting member of the capacitor device 102described on later pages herein. The concave-like groove 153 may be aconvex-like protrusion, in which case, the convex-like protrusionprovided on the connecting member of the capacitor device 102 is formedas a concave-like groove instead.

In the present embodiment, one principal plane (left side on the paper)of the first molded section 151 is hereinafter defined as a firstprincipal plane, and the other principal plane (right side on the paper)as a second principal plane. Also, one lateral side (front side on thepaper) of the first molded section 151 is defined as a first lateralside, and the other lateral side (rear side on the paper) as a secondlateral side. In addition, one longitudinal side (upper side on thepaper) is defined as a first longitudinal side, and the otherlongitudinal side (lower side on the paper) as a second longitudinalside. Furthermore, one side (left side on the paper) in the thicknessdirection of the first molded section 151 is defined as a firstprincipal plane side, and the other side (right side on the paper) as asecond principal plane side.

Inside the first molded section 151, the M-electrode 120, the G-wire162, and the S-wire 163 are arranged at the first principal side, andthe P-electrode 130, the N-electrode 140, the G-wire 160, and the S-wire161 are arranged at the second principal side. Respective electrodesurfaces of the M-electrode 120, P-electrode 130, N-electrode 140 arearranged in parallel to one another. The four electrode surfaces arealso maintained in a parallel arrangement relationship with respect tothe first and second principal planes of the first molded section 151.

The M-electrode 120 is constituted by a heat-releasing section 121, alead wire 122, and a lead terminal 123.

The heat-releasing section 121 constitutes a mounting circuit board andheat-releasing circuit board for semiconductor chips, and is arectangular flat-plate section extending along, and in parallel to, thefirst principal plane of the first molded section 151. Long sides of theheat-releasing section 121 extend in the same direction as that of thelong sides of the first molded section 151, and are shorter than thelong sides of the first molded section 151. Short sides of theheat-releasing section 121 extend in the same direction as that of theshort sides of the first molded section 151, and are shorter than thelong sides of the first molded section 151. A first principal plane ofthe heat-releasing section 121 is formed as a heat release plane. Theheat release plane of the heat-releasing section 121 becomes exposed atthe surface of the first principal plane of the first molded section 151so as to be flush with the first principal plane thereof. A secondprincipal plane of the heat-releasing section 121 is formed as amounting surface.

The lead wire 122 constituting an output end of an arm is formed at afirst longitudinal edge of the heat-releasing section 121. The lead wire122 is a rectangular flat-plate section bent at right angles to a firstlongitudinal side of the heat-releasing section 121 from a centralportion of a first longitudinal peripheral plane thereof, then extendingstraightly, and further extended outward from the first longitudinalperipheral plane of the first molded section 151. The lead wire 122 isdisposed on the same plane as that of the heat-releasing section 121,and is formed integrally therewith. Short sides of the lead wire 122extend in the same direction as that of the long sides of the firstmolded section 151, and are shorter than the short sides of theheat-releasing section 121. Long sides of the lead wire 122 extend to afirst longitudinal side thereof.

The lead terminal 123 constituting a connecting portion of the outputend of the arm is formed at a first longitudinal edge of the lead wire122. The first longitudinal edge of the lead wire 122 further extendsstraightly to the first longitudinal side thereof in that state, wherebythe lead terminal 123 is formed as a rectangular flat-plate section. Thelead terminal 123 is disposed on the same plane as that of the lead wire122, and is formed integrally therewith. A principal plane (terminalsurface) of the lead terminal 123 is formed with a circular screw hole124 cut through in the thickness direction of the first molded section151.

The P-electrode 130 and the N-electrode 140 are arranged at a sectionopposed to a second principal plane side of the M-electrode 120.

The N-electrode 140 is constituted by a heat-releasing section 141, alead wire 142, a lead terminal 143, a first bend 144, and a second bend145.

The heat-releasing section 141 constitutes a mounting circuit board andheat-releasing circuit board for semiconductor chips, and is arectangular flat-plate section extending along, and in parallel to, thesecond principal plane of the first molded section 151. Short sides ofthe heat-releasing section 141 extend in the same direction as that ofthe long sides of the first molded section 151, and are shorter than thelong sides of the first molded section 151. Long sides of theheat-releasing section 141 extend in the same direction as that of theshort sides of the first molded section 151, and are equal to the shortsides of the first molded section 151 in terms of length. A secondprincipal plane of the heat-releasing section 141 is formed as a heatrelease plane. The heat release plane of the heat-releasing section 141becomes exposed at the surface of the second principal plane of thefirst molded section 151 so as to be flush with the second principalplane thereof. A first principal plane of the heat-releasing section 141is formed as a mounting surface.

The first bend 144 that changes a conductor position is formed at asecond lateral edge of the heat-releasing section 141. The secondlateral edge of the heat-releasing section 141 is bent intact at rightangles to the M-electrode 120 and extends straightly thereto, wherebythe first bend 144 is formed as a rectangular flat-plate section. Thefirst bend 144 is formed integrally with the heat-releasing section 141.Long sides of the first bend 144 extend in the same direction as that ofthe long sides of the heat-releasing section 141, and are equal to thelong sides thereof in terms of length. Short sides of the first bend 144extend in a direction of the M-electrode 120, and are shorter than theshort sides of the lead wire 122.

The lead wire 142 constituting a high-potential input end of the arm isformed at an edge of a first principal plane of the first bend 144. Theedge of the first principal plane of the first bend 144 is bent intactat right angles to a second lateral edge thereof, then after extendingstraightly along, and in parallel to, the mounting plane of theheat-releasing section 121, further bent at right angles to a secondlongitudinal edge of the first bend 144, and extending straightly inparallel with respect to the mounting plane of the heat-releasingsection 121. The lead wire 142 is thus formed as an L-shaped flat-platesection. The lead wire 142 is disposed on a plane different from that ofthe heat-releasing section 121, and is formed integrally with the firstbend 144. In this fashion, a position of the lead wire 142 is changed bythe first bend 144, and is closer to the M-electrode 120 than to theheat-releasing section 121.

Of two edges of the L-shaped flat-plate conductor constituting the leadwire 142, the edge opposite to that facing the first bend 144 (i.e., theedge extending towards the second longitudinal side) is formed with thesecond bend 145 that changes the conductor position. The side edge ofthe second bend 145 that extends towards the second longitudinal side ofthe lead wire 142 is bent intact at right angles to the M-electrode 120and extends straightly thereto, whereby the second bend 145 is formed asa rectangular flat-plate section. The second bend 145 is formedintegrally with the lead wire 142. Long sides of the second bend 145extend in the same direction as that of a side of the side edgeextending towards the second longitudinal side of the lead wire 142, andhave a length equal to that of the side of the side edge extendingtowards the second longitudinal side of the lead wire 142. Short sidesof the second bend 145 extend in the direction of the M-electrode 120,and are shorter than the short sides of the lead wire 122.

The lead terminal 143 constituting a connecting portion of anotheroutput end of the arm is formed at an edge of a first principal plane ofthe second bend 145. The first principal plane side edge of the secondbend 145 is bent intact at right angles to the second longitudinal side,then extends straightly in parallel with respect to the mounting planeof the heat-releasing section 121, and further extends outward from thesecond longitudinal side edge of the second molded section 152. The leadterminal 143 is thus formed as a rectangular flat-plate section. Thelead terminal 143 is disposed on a plane different from those of theheat-releasing section 141 and lead wire 142 (that is, the lead terminal143 is disposed on the same plane as that of the heat-releasing section121, directly under the second longitudinal side thereof). The leadterminal 143 is formed integrally with the second bend 145. In thisfashion, a position of the lead terminal 143 is changed by the secondbend 145, and is closer to the M-electrode 120 than to theheat-releasing section 141 and the lead wire 142. Short sides of thelead terminal 143 extend in the same direction as that of the long sidesof the heat-releasing section 141, and are shorter than the long sidesthereof. Long sides of the lead terminal 143 extend in the samedirection as that of the long sides of the second bend 145, and equal tothe long sides thereof in terms of length. A circular screw hole 146extending through in the thickness direction of the first molded section151 is formed at a second lateral side edge of a principal plane(terminal surface) of the lead terminal 143.

The P-electrode 130 is constituted by a heat-releasing section 131, alead wire 132, a lead terminal 133, and a bend 134.

The heat-releasing section 131 constitutes a mounting circuit board andheat-releasing circuit board for semiconductor chips, and is arectangular flat-plate section extending along, and in parallel to, thesecond principal plane of the first molded section 151. Short sides ofthe heat-releasing section 131 extend in the same direction as that ofthe long sides of the first molded section 151, and are shorter than thelong sides of the first molded section 151. Long sides of theheat-releasing section 131 extend in the same direction as that of theshort sides of the first molded section 151, and are equal to the shortsides of the first molded section 151 in length. A second principalplane of the heat-releasing section 131 forms a heat release plane. Theheat release plane of the heat-releasing section 131 becomes exposed atthe surface of the second principal plane of the first molded section151 so as to be flush with the second principal plane thereof. A firstprincipal plane of the heat-releasing section 131 forms a mountingsurface.

The lead wire 132 constituting a low-potential input end of the arm isformed at a second lateral side edge of the heat-releasing section 131.A first lateral side edge of the heat-releasing section 131 extendsintact along the second principal plane of the lead wire 142, inparallel to the second principal plane thereof, and further straightlytowards the first lateral side. Additionally, the first lateral sideedge of the heat-releasing section 131 is bent at right angles to thesecond longitudinal side and extends straightly along, and in parallelto, the second principal plane of the lead wire 142. The lead wire 132is thus formed as an L-shaped flat-plate section. The lead wire 132 isdisposed on the same plane as that of the heat-releasing section 131,and is formed integrally therewith. The second principal plane of thelead wire 142 constitutes a heat release plane of the semiconductorchip.

In the present embodiment, the second principal plane of the lead wire132 is constructed as a heat release plane, and is exposed from thesecond principal plane of the first molded section 151. However, thisheat release plane may be covered with mold resin.

Of two edges of the L-shaped flat-plate conductor constituting the leadwire 132, the edge opposite to that facing the heat-releasing section131 (i.e., the edge extending towards the second longitudinal side) isformed with the bend 134 that changes the conductor position. The edgeof the bend 134 that extends towards the second longitudinal side of thelead wire 132 is bent at right angles to the opposite side with respectto the M-electrode 120, whereby the bend 134 is formed as a rectangularflat-plate section. The bend 134 is formed integrally with the lead wire132. Long sides of the bend 134 extend in the same direction as that ofa side of the edge extending towards the second longitudinal side of thelead wire 132, and have a length equal to that of the side of the edgeextending towards the second longitudinal side of the lead wire 132.Short sides of the bend 134 extend in the direction of the M-electrode120, and are shorter than the short sides of the lead wire 122.

The lead terminal 133 constituting a connecting portion of alow-potential input end of the arm is formed at a side edge of a secondprincipal plane of the bend 134. The second principal plane side edge ofthe bend 134 is bent intact at right angles to the second longitudinalside, then extends straightly along, and in parallel to, the secondprincipal plane of the heat-releasing section 143, and further extendsoutward from the second longitudinal side edge of the second moldedsection 152. The lead terminal 133 is thus formed as a rectangularflat-plate section. The lead terminal 133 is disposed on a planedifferent from those of the heat-releasing section 131 and lead wire 132(that is, the lead terminal 143 is disposed externally to the secondprincipal plane of the first molded section 151). The lead terminal 133is formed integrally with the bend 134. In this fashion, a position ofthe lead terminal 133 is changed by the bend 134, and is more distantfrom the M-electrode 120 than from the heat-releasing section 131 andthe lead wire 132. Short sides of the lead terminal 133 extend in thesame direction as that of the long sides of the heat-releasing section131, and are shorter than the long sides of the heat-releasing section141. Long sides of the lead terminal 133 extend in the same direction asthat of the long sides of the bend 134, and equal to the long sidesthereof in terms of length. A circular screw hole 135 extending throughin the thickness direction of the first molded section 151 is formed ata first lateral side edge of a principal plane (terminal surface) of thelead terminal 133.

Between the mounting surfaces of the heat-releasing sections 121 and131, semiconductor chips that constitute the upper-arm IGBT 111 and theupper-arm diode 112 are arranged next to each other in a longitudinaldirection, and the semiconductor chips are mounted at the second lateralside edge.

In the present embodiment, the semiconductor chip constituting theupper-arm IGBT 111 is hereinafter referred to as the HI chip, and thesemiconductor chip constituting the upper-arm diode 112, as the HD chip.

For the HI chip disposed at the first longitudinal side, the chipsurface that faces the second principal plane is solder-bonded to themounting surface of the heat-releasing section 131 such that thecollector electrode formed on the chip surface facing the secondprincipal plane is electrically connected to the mounting surface of theheat-releasing section 131. For the HD chip disposed at the secondlongitudinal side, the chip surface that faces the second principalplane is solder-bonded to the mounting surface of the heat-releasingsection 131 such that the cathodic electrode formed on the chip surfacefacing the second principal plane is electrically connected to themounting surface of the heat-releasing section 131. A second principalplane of the buffering member 113 is solder-bonded to the chip surfaceof the HI chip at the first principal plane such that the emitterelectrode and the buffering member 113 are electrically connected. Asecond principal plane of the buffering member 114 is solder-bonded tothe chip surface of the HD chip at the first principal plane such thatthe anodic electrode and the buffering member 114 are electricallyconnected. First principal planes of the buffering members 113, 114 aresolder-bonded to the mounting surface of the heat-releasing section 121.In this way, the HI chip and the HD chip are mounted in a stacked formbetween the mounting surfaces of the heat-releasing sections 121 and131.

Between the mounting surfaces of the heat-releasing sections 121 and141, semiconductor chips that constitute the lower-arm IGBT 111 and thelower-arm diode 112 are arranged next to each other in a longitudinaldirection, and the semiconductor chips are mounted at the first lateralside edge.

In the present embodiment, the semiconductor chip constituting thelower-arm IGBT 111 is hereinafter referred to as the LI chip, and thesemiconductor chip constituting the upper-arm diode 112, as the LD chip.

For the LI chip disposed at the first longitudinal side, the chipsurface that faces the first principal plane is solder-bonded to themounting surface of the heat-releasing section 121 such that thecollector electrode formed on the chip surface facing the firstprincipal plane is electrically connected to the mounting surface of theheat-releasing section 121. For the LD chip disposed at the secondlongitudinal side, the chip surface that faces the first principal planeis solder-bonded to the mounting surface of the heat-releasing section121 such that the cathodic electrode formed on the chip surface facingthe first principal plane is electrically connected to the mountingsurface of the heat-releasing section 121. The first principal plane ofthe buffering member 113 is solder-bonded to the chip surface of the LIchip at the second principal plane such that the emitter electrode andthe buffering member 113 are electrically connected. The first principalplane of the buffering member 114 is solder-bonded to the chip surfaceof the LD chip at the second principal plane such that the anodicelectrode and the buffering member 114 are electrically connected. Thesecond principal planes of the buffering members 113, 114 aresolder-bonded to the mounting surface of the heat-releasing section 141.In this way, the LI chip and the LD chip are mounted in a stacked formbetween the mounting surfaces of the heat-releasing sections 121 and141.

The buffering members 113, 114 are spacers that are used for alleviatingthermal stresses, for establishing electrical and thermal connectionbetween the HI chip, the HD chip, and the heat-releasing section 121,and for establishing electrical and thermal connection between the LIchip, the LD chip, and the heat-releasing section 141. The spacers areblock structures of a rectangular solid shape, both made of a thermallyconductive and electrically conductive metal, for example, an alloy ofmolybdenum and copper.

An example of bonding the buffering member 113 to the HI and LI chipsurfaces facing the emitter electrode, and bonding the buffering member114 to the HD and LD chip surfaces facing the cathodic electrode, hasbeen described in the present embodiment. However, the buffering members113 and 114 may be bonded to the chip surfaces facing in oppositedirections.

In addition, if the buffering member 113 bonded to the HI chip surfaceat the emitter electrode side is bonded to the HI chip surface at thecollector electrode side instead and the buffering member 114 bonded tothe HD chip surface at the anodic electrode side is bonded to the HDchip surface at the cathodic electrode side, cooling capabilities of theHI chip and HD chip at the heat-releasing section 121 of the M-electrode120 and cooling capabilities of the LI chip and LD chip can be made toequal each other.

A gate electrode and a current detection electrode are formed on thechip surface of the HI chip at the first principal plane and on the chipsurface of the LI chip at the second principal plane. A G-wire 160 andan S-wire 161 are electrically connected to the gate electrode andcurrent detection electrode, respectively, of the HI chip by bonding analuminum wire between both. A G-wire 162 and an S-wire 163 areelectrically connected to the gate electrode and current detectionelectrode, respectively, the LI chip by bonding an aluminum wire betweenboth.

The G-wire 160 and the S-wire 161, both juxtaposed in a long-sidedirection and arranged at the first longitudinal side of the secondlateral side edge of the P-electrode 130, extend towards the firstlongitudinal side and then further extend outward from the firstlongitudinal peripheral plane of the first molded section 151. TheG-wire 162 and the S-wire 163 juxtaposed in a long-side direction andarranged at the first longitudinal side of the first lateral side edgeof the M-electrode 120, extend towards the first longitudinal side andthen further extend outward from the first longitudinal peripheral planeof the first molded section 151.

When the electric circuit device 110 is assembled, the first principalplane-side chip surfaces of the LI chip and the LD chip are bonded tothe mounting surface of the heat-releasing section 121 of theM-electrode 120 first. Next, the G-wire 162 is bonded to the gateelectrode of the LI chip, and the S-wire 163, to the current detectionelectrode of the LI chip. Also, the buffering member 113 is bonded tothe chip surface of the LI chip that faces the second principal plane,and the buffering member 114, to the chip surface of the LD chip thatfaces the second principal plane. A first assembly (see FIG. 1) at theM-electrode 120 is now completed.

Next, the first assembly and the N-electrode 140 are opposed to eachother and the mounting surface of the heat-releasing section 141 of theN-electrode 140 is bonded to the planes of the buffering members 113,114 that face the second principal plane. The N-electrode 140 is thusmounted in the first assembly so that the first principal plane of thelead wire 142 of the N-electrode 140 is as close as possible to themounting surface of the heat-releasing section 121 of the M-electrode120 via a clearance 117. The clearance 117 has a magnitude which, whenthe clearance 117 is filled with an insulating member (mold resin), anelectrical insulating distance can be obtained between the M-electrode120 and the N-electrode 140. The clearance 117 is determined by thelength of the first bend 144 in the short-side direction thereof. Asecond assembly including the first assembly and the N-electrode 120 isnow completed.

Next, the second principal plane-side chip surfaces of the HI chip andthe HD chip are bonded to the mounting surface of the heat-releasingsection 131 of the P-electrode 130. Next, the G-wire 160 is bonded tothe gate electrode of the HI chip, and the S-wire 161, to the currentdetection electrode of the HI chip. Also, the buffering member 113 isbonded to the chip surface of the HI chip that faces the first principalplane, and the buffering member 114, to the chip surface of the HD chipthat faces the first principal plane. A third assembly (see FIG. 1) atthe P-electrode 130 is now completed. In the present embodiment, thethird assembly is manufactured after the second assembly has beenmanufactured. However, the third assembly may be manufacturedsimultaneously with the first assembly, or after the first assembly hasbeen manufactured, or before the second assembly is manufactured.

Next, the second assembly and the third assembly are opposed to eachother and the mounting surface of the heat-releasing section 121 of theM-electrode 120 is bonded to the planes of the buffering members 113,114 that face the first principal plane. The third assembly is thusmounted in the second assembly so that the second principal plane of thelead wire 142 of the N-electrode 140 is closely opposed to the firstprincipal plane of the heat-releasing section 132 of the P-electrode 130via a clearance 118. Also, the third assembly is mounted in the secondassembly so that the first lateral side edge of the lead wire 132 isclose to the second lateral side edge of the heat-releasing section 141via a clearance 116. Additionally, the third assembly is thus mounted inthe second assembly so that the first principal plane of the leadterminal 133 is opposed to the second principal plane of the leadterminal 143 via a clearance 115. The clearance 116 has a magnitudewhich, when the clearance 116 is filled with an insulating member (moldresin), an electrical insulating distance can be obtained between theP-electrode 130 and the N-electrode 140. The clearance 116 is determinedby the lengths of the heat-releasing section 131, lead wire 132, andheat-releasing section 141, in the long-side directions of each. Theclearance 118 has a magnitude which, when the clearance 118 is filledwith an insulating member (mold resin), an electrical insulatingdistance can be obtained between the P-electrode 130 and the N-electrode140. The clearance 118 is determined by the length of the first bend 144in the short-side direction thereof. The clearance 115 has a magnitudethat makes it possible for a connection member of the later-describedcapacitor device 102 to be inserted (engaged) without a clearance. Theclearance 115 is determined by the lengths of the bend 134 and secondbend 145 in the thickness direction of the first molded section 151. Afourth assembly including the second assembly and the third assembly isnow completed (see FIG. 2).

Next, the fourth assembly is fixed using a jig or a metallic mold. Next,heat and pressure are applied to a molded resin structure and then moldresin is poured into the jig or the metallic mold. Thus, a clearancebetween the fourth assembly and the jig or the metallic mold, and aclearance inside the fourth assembly are filled with the mold resin,whereby the molded body 150 shown in FIG. 3 is completed. In this case,the heat release plane of the heat-releasing section 121 of theM-electrode 120 becomes exposed at the surface of the first principalplane of the first molded section 150. Also, the heat release plane ofthe heat-releasing section 131 of the P-electrode 130, the heat releaseplane of the lead wire 132, and the heat release plane of theheat-releasing section 141 of the N-electrode 140 become exposed, injuxtaposed form in the long-side direction, at the surface of the secondprincipal plane of the first molded section 151, since theheat-releasing section 131 of the P-electrode 130, the lead wire 132,and the heat-releasing sections 141 of the N-electrode 140 are arrangedon the same plane. Additionally, the lead wire 122 of the M-electrode120, the lead terminal 123, the G-wires 160, 162, and the S-wires 161,163 are routed outward from the first longitudinal principal plane ofthe first molded section 151. Furthermore, the lead wire 133 of theP-electrode 130 and the lead terminal 143 of the N-electrode 140 arerouted outward from the second longitudinal plane of the second moldedsection 152.

The mold resin has an electrical insulating property, and when used tofill the fourth assembly, the mold resin provides electrical insulationbetween the M-electrode 120, the P-electrode 130, the N-electrode 140,the G-wires 160, 162, and the S-wires 161, 163.

The screw hole 135 provided in the lead terminal 133, and the screw hole146 provided in the lead terminal 143 are formed at opposite positionsin the long-side direction. Thus, when the lead terminals 133 and 143are opposed to each other, the screw holes 135 and 146 skew with respectto each other in the long-side direction.

According to the present embodiment described above, the N-electrode 140is bent at the first bend 144 in the direction opposite to theP-electrode 130, the lead wire 132 of the P-electrode 130 and the leadwire 142 of the N-electrode 140 are opposed in parallel to each other inproximity to the bending direction of the N-electrode 140, and the leadterminals 133 and 143 are opposed in parallel to each other. Therefore,when a positive current flows into the lead wire 132 and the leadterminal 133 and a negative current equal to the positive current inmagnitude and opposite in direction flows into the lead wire 142 and thelead terminal 143, a magnetic field generated by the positive currentcan be offset by a magnetic field generated by the negative current.Thus, according to the present embodiment, the magnetic field offseteffect makes it possible to reduce the line inductance developed betweenthe lead wire 132, 142 and the lead terminal 133, 143.

FIGS. 6 and 7 show more specifically a line inductance reduction effectobtainable in the above configuration. An example in which the IGBT 111at the upper-arm side is switched from off to on is described below inthe present embodiment.

As shown in FIG. 6, line inductance 106 exists between the collectorelectrode line (lead wire 132 and lead terminal 133) of the upper-armIGBT 111 and the emitter electrode wiring (lead wire 142 and leadterminal 143) of the lower-arm IGBT 111. Also, line inductance 105exists between the positive and negative lines of the capacitor device102, as shown in FIG. 6. The electric circuit device 110 of the presentembodiment is constructed so as to reduce the line inductance 106. Asdescribed later herein, the line inductance 115 is also reduced in thepresent embodiment.

When the upper-arm IGBT 111 is switched from off to on, a recoverycurrent 107 routed from the DC positive-polarity side through theupper-arm IGBT 111 and the lower-arm diode 112 to the DCnegative-polarity side flows into the arm for a moment. The arrow of asolid line, denoted as reference number 108, indicates a load currentthat flows when the upper-arm IGBT 111 is in a turn-on state.

As shown in FIG. 7, the recovery current 107 in the electric circuitdevice 110 flows from the led terminal 133 of the P-electrode 130 intothe lead terminal 143 of the N-electrode 140. At this time, recoverycurrents that flow into the lead wire 132 and the lead wire 142 of theN-electrode 140 are equal in magnitude and opposite in direction.Recovery currents that flow into the lead wire 133 of the P-electrode130 and the lead wire 143 of the N-electrode 140 are also equal inmagnitude and opposite in direction. At the opposed sections describedabove, therefore, a magnetic field generated by the recovery currentflowing into one side is offset by a magnetic field generated by therecovery current flowing into the other side, and the line inductance106 is resultingly reduced.

Essentially the same effect as the above, is also expected to beobtainable when the upper-arm IGBT 111 is switched from on to off, whenthe lower-arm IGBT 111 is switched from off to on, and when thelower-arm IGBT 111 is switched from on to off.

According to the present embodiment, therefore, since the lineinductance 106 in the electric circuit device 110 can be reduced, lossduring the switching of the IGBT 111 can be reduced and the amount ofheat generated thereby can also be reduced. Hence, according to thepresent embodiment, the electric circuit device 110 can be constructedusing a more compact semiconductor chip that constitutes the IGBT 111,and thus the electric circuit device 110 can be miniaturized.

Additionally, according to the present embodiment, the semiconductorchips constituting the upper arm IGBT 111 and diode 112 are sandwichedusing the P-electrode 130 and the M-electrode 120, and the semiconductorchips constituting the lower-arm IGBT 111 and diode 112 are sandwichedusing the N-electrode 140 and the M-electrode 120. Furthermore, theplane opposite to the mounting surface of the semiconductor chips of theP-electrode 130 and M-electrode 120, and the plane opposite to themounting surface of the semiconductor chips of the N-electrode 140 andM-electrode 120 are exposed as heat release planes, at the surface ofthe first molded section 151. The heat generated by the semiconductorchips can be released from both chip surfaces thereof to outside viaeach electrode. This makes it possible, according to the presentembodiment, to release a greater amount of heat from the semiconductorchips and improve cooling capabilities of the electric circuit device110. Hence, according to the present embodiment, the electric circuitdevice 110 can be constructed using smaller semiconductor chips thatconstitute the IGBTs 111 and the diodes 112, and thus the electriccircuit device 110 can be miniaturized.

As described above, the present embodiment makes it possible to achieveline inductance reduction in the electric circuit device 110 and theimprovement of its cooling capabilities at the same time.

Next, a configuration of an actual inverter 100 (300) with theabove-described electric circuit device 110 mounted therein will bedescribed using FIGS. 8 to 18.

The inverter 100 (300) includes a semiconductor module 101, a capacitordevice 102, and a circuit board unit 190 constituting a controller 103.

The semiconductor module 101 includes a heat release base 170 and anelectric circuit device 110 mounted on the heat release base 170.

The heat release base 170, a heat-releasing element made of a metalexcellent in thermal conductivity, such as aluminum, is a structure thatincludes a base unit for mounting and cooling the electric circuitdevice 110, a collar constituting an installation section with respectto an enclosure, and a cooling fin 174 for cooling the capacitor device102. The base unit, the collar, and the cooling fin 174 are integrallyformed by die-processing or cutting the above metallic material. Thebase unit is constructed of a block structure having a rectangular solidshape.

Hereinafter, in the present embodiment, when the base unit of the heatrelease base 170 is dimensionally maintained in a relationship of thedepth is larger than the width and the height is smaller than the width,a depth direction of the base unit is defined as a longitudinaldirection, a horizontal (width) direction as a lateral direction, and aheight direction as a vertical direction or a thickness direction.

Centrally in the lateral direction of the base unit of the heat releasebase 170, three electric circuit device insertion sections 172 extendingupright in the vertical direction from a lower face 175, towards anupper face 173, are arranged in line in the longitudinal direction. Eachelectric circuit device insertion section 172 is of a rectangularcross-sectional shape. In this state, the electric circuit deviceinsertion section 172 is provided so that a direction in which its longsides extend is the same as the longitudinal direction. Side walls 176formed at both sides of the electric circuit device insertion section172, in the lateral direction thereof, each constitute a coolingsurface. Each side wall 176 has a resin gate 177 at both ends in alongitudinal direction thereof, and centrally in the longitudinaldirection. Each resin gate 177 is a cross-sectionally concave grooveextending in the vertical direction. The resin gate 177, across-sectionally concave groove extending in the vertical direction, isalso formed centrally in a lateral direction of each side wall formed atboth sides of the electric circuit device insertion section 172 in thelateral direction thereof. The resin gate 177 is used to pour resin intoa clearance between the electric circuit device insertion section 172and the electric circuit device 110 when the electric circuit device 110is inserted into the electric circuit device insertion section 172. Theresin gate 177 is constructed so that the cross-sectionally concavegroove avoids interference with the heat release planes of the electriccircuit device 110.

The base unit of the heat release base 170 internally has a coolingmedium flow channel 171 at both ends in the lateral direction. Thecooling medium flow channels 171 each extending through from onelongitudinal side face to another are arranged at lateral positions inparallel so that each side wall 176 is sandwiched from both lateralsides, and so as to be parallel to the side wall 176. Each coolingmedium flow channel 171 is rectangular in cross-sectional shape. Acoolant (water) flows as the cooling medium into the cooling medium flowchannel 171.

A longitudinal dimension of the electric circuit device insertionsection 172 (i.e., a distance between the side walls 176) is slightlylarger than a dimension of the electric circuit device 110 in athickness direction thereof (i.e., a distance between the first andsecond principal planes of the molded section 150) when the electriccircuit device 110 is inserted into the electric circuit deviceinsertion section 172. When the electric circuit device 110 is insertedinto the electric circuit device insertion section 172, therefore, aclearance is formed between the first principal plane of the firstmolded section 151 and one side wall 176 and between the secondprincipal plane of the first molded section 151 and the other side wall176. These clearances are each filled in with resin 200 of high thermalconductivity.

The collars of the heat release base 170 are sections provided so as toprotrude upward from both upper side faces of the base unit of the heatrelease base 170 in the lateral direction of the base unit, and thecollars are constructed of a plate member having an L-shapedcross-sectional form. When the collars of the heat release base 170 arefixed to collars or installation portions of metallic casing (notshown), the semiconductor module 101 is stored into the casing and fixedwith the capacitor device 102 and the circuit board unit 190 remainingmounted in the module 101 (see FIG. 8). The inside of the casing ishermetically enclosed by shrouding an opening of the casing with ametallic cover or lid, whereby the casing is waterproofed (water-sealed)and electromagnetically shielded.

The cooling fin 174 is a section provided so as to protrudeperpendicularly in a downward direction from both lateral ends of thebase unit lower face 175 of the heat release base 170. The cooling fin174, an L-shaped plate member in cross section, is provided over entirelongitudinal length of the base unit of the heat release base 170. Aplurality of screw insertion holes 179 are formed in a side wall of thecooling fin 174. The screw insertion holes 179 are round through-holesextending through the side wall of the cooling fin 174 in a lateraldirection thereof, and these holes are provided to insert screws fromthe side wall of the cooling fin 174 into a region surrounded thereby.

The electric circuit device 110 is inserted from the lower face 175 intothe electric circuit device insertion section 172 and then insert-moldedwith the highly heat-conductive resin 200. The electric circuit device110 is positioned using the second molded section 152. That is to say,since a dimension of the second molded section 152 in a thicknessdirection thereof is larger than the lateral dimension of the electriccircuit device 110, when the electric circuit device 110 is insertedfrom the lower face 175 into the electric circuit device insertionsection 172, the second molded section 152 abuts the lower face 175 andfunctions as a stopper.

The highly heat-conductive resin 200 has high thermal conductivity andan excellent electrical insulating property, and this resin is a mixtureformed by, for example, impregnating epoxy resin with silica. The kindof substance with which to impregnate a resin agent such as epoxy resincan be alumina, aluminum nitride, boron nitride, or the like, instead ofsilica. The clearance between the first principal plane of the firstmolded section 151 and one side wall 176, the clearance between thesecond principal plane of the first molded section 151 and the otherside wall 176, the clearance between the lower-stage step surface of thesecond molded section 152 and the lower face 175, and internal spaces ofthe resin gates 177 are filled in with the highly heat-conductive resin200 that has been poured via the resin gates 177. Also, portions of theelectric circuit device 110 exposed from the base unit upper face 173 ofthe heat release base 170 (i.e., the exposed portion at the firstlongitudinal side of the first molded section 151, a portion of the leadwire 122, and portions of the G-wires 160, 162 and S-wires 161, 163) arecovered with the highly heat-conductive resin 200 so that a range ofpackaging therewith is dimensionally greater than the opening in theelectric circuit device insertion section 172. Thus, the electriccircuit device 110 is fixed in an electrically insulated condition tothe base unit of the heat release base 170. Additionally, the heatrelease planes of the electric circuit device 110 (namely, the principalplane side of the heat-releasing section 121, the second principal planeside of the heat-releasing section 131, 141 each, and that of the leadwire 122) are thermally connected in an electrically insulated conditionto the side wall 176.

According to the present embodiment, since the heat release planes ofthe electric circuit device 110 (namely, the principal plane side of theheat-releasing section 121, the second principal plane side of theheat-releasing section 131, 141 each, and that of the lead wire 122) arethermally connected in an electrically insulated condition to the sidewall 176, heat from both sides of the electric circuit device 110 istransferred to the side wall 176 via the highly heat-conductive resin200 and then further transferred from the side wall 176 to the coolantflowing into the cooling medium flow channels 171. According to thepresent embodiment, since both sides of each semiconductor chip insidethe electric circuit device 110 can thus be cooled, cooling performancethereof can be improved and the electric circuit device 110 itself canbe constructed using smaller semiconductor chips. According to thepresent embodiment, therefore, it is possible to miniaturize theelectric circuit device 110 and thus to miniaturize the semiconductormodule 101 in which the electric circuit device 110 is to be mounted.

At a lower section of the region surrounded by the cooling fin 174 isdisposed the capacitor device 102, an upper section of which (i.e., anupper section close to the lower face 175) are disposed the leadterminals 133, 143 extending from the second longitudinal side of thesecond molded section 121, towards the capacitor device 102. Thecapacitor device 102 and the lead terminals 133, 143 are electricallyconnected so as to match the polarities of the capacitor device 102 andthose of the lead terminals 133, 143.

The capacitor device 102 includes a capacitor block 180, a connectionmember 183, a positive-polarity capacitor terminal 181, anegative-polarity capacitor terminal 182, and an electrical insulatingsheet 184. The positive-polarity capacitor terminal 181 and thenegative-polarity capacitor terminal 182 are both formed using aflat-plate conductor made of a metal such as a copper alloy or copperexcellent in thermal conductivity and in electrical conductivity. Theconnection member 183 is formed of an insulating member. Polybutylenetelephthalate (PBT), for example, is used as the insulating member.

Hereinafter, in the present embodiment, the capacitor block 180 isreferred to as the C-block 180, the positive-polarity capacitor terminal181 as the PC terminal 181, and the negative-polarity capacitor terminal182 as the NC terminal 182.

The C-block 180 is a block structure of a rectangular solid shape,having a capacitor element in a casing. A longitudinal dimension of theC-block 180 is the same as that of the heat release base 170. TheC-block 180 has a lateral dimension that allows the C-block to lieproperly in an internal space of the cooling fin 174. Both lateral sidesof the C-block 180 abut on an inner surface of the side wall of thecooling fin 174. This arrangement causes the C-block 180 and the coolingmedium flow channels 171 to be thermally connected via the heat releasebase 170. Heat from the C-block 180 is transferred to the base unit ofthe heat release base 170 via the cooling fin 174 and then furthertransferred from the base unit to the coolant flowing into the coolingmedium flow channels 171.

A terminal unit that includes the PC terminal 181, the NC terminal 182,and the insulating sheet 184, is disposed on an upper face of theC-block 180. In terminal unit having the PC terminal 181 and the NCterminal 182 arranged in stacked form in the lateral direction with theinsulating sheet 184 positioned between both, the PC terminal 181 andthe NC terminal 182 protrude perpendicularly from a lateral centralsection of the C-block 180, towards the lower face 175, and extend inparallel in the longitudinal direction in association with the leadterminal 133, 144. The PC terminal 181 and NC terminal 182, afterprotruding, are both bent outward (towards the opposite side to thesandwiching side of the insulating sheet 184) in the respective lateraldirections at right angles and then extend straightly. The PC terminal181 and the NC terminal 182 are further bent at right angles towards thelower face 175, then extend straightly, and face in the lateraldirection in a longitudinally parallel condition via a spatial section.The insulating sheet 184, after protruding, further extends straightlytowards the lower face 175 and leads to a position closer thereto thanto bends of the PC terminal 181 and the NC terminal 182.

A screw hole 187 is formed in the PC terminal 181. A screw hole 188 isformed in the NC terminal 182. The screw hole 187 is a through-holepenetrating a terminal surface of the PC terminal 181 in a lateraldirection thereof, and when the PC terminal 181 and the lead terminal133 are connected, a position of an opening in the PC terminal 181matches a position of an opening of the screw hole 135 in the leadterminal 133. The screw hole 188 is a through-hole extending through aterminal surface of the NC terminal 182 in a lateral direction thereof,and when the NC terminal 182 is connected with the lead terminal 143, aposition of an opening in the NC terminal 182 matches a position of anopening of the screw hole 146 in the lead terminal 143. For this reason,the screw hole 187 in the PC terminal 181 and the screw hole 188 in theNC terminal 182 are alternately arranged in the longitudinal direction.

The connection member 183 is disposed in the space formed between the PCterminal 181 and the NC terminal 182. The connection member 183 is ablock structure of a polyhedral solid shape, held in a sandwichedcondition between the PC terminal 181 and the NC terminal 182 from bothlateral sides thereof. The connection member 183 is used as anelectrical insulating member between the PC terminal 181 and the NCterminal 182, and as a connection member between the PC terminal 181,the NC terminal 182, and the lead terminal 133, 144. The block structureforming the connection member is formed up of a convex protrusion 186disposed on the plane facing in the same direction as that of the lowerface 175 of the rectangular solid, and a concave groove 185 disposed atthe side of the capacitor block 180 of a rectangular solid shape. Theprotrusion 186 and the groove 185 are continuously provided in thelongitudinal direction. A nut-containing portion 119 is formed at bothsides in the lateral direction of the block structure which forms theconnection member 183. The nut-containing portions 119 are each abottomed hexagonal hole opened from the lateral direction of the blockstructure, both lateral sides thereof. When the connection member 183 isinserted into the space between the PC terminal 181 and the NC terminal182, a position of the above opening matches a position of the openscrew hole 187, 188. For this reason, the nut-containing portion 119 atone side in the lateral direction of the connection member 183, and thenut-containing portion 119 at the other side in the lateral directionare arranged in an offset condition in the longitudinal direction. Eachnut-containing portion 119 contains a nut 189.

Prior to electrical connection between the PC terminal 181 and NCterminal 182 of the capacitor device 102 and the lead terminals 133,143, respectively, of the semiconductor module 101, the connectionmember 183 is inserted into the space between the PC terminal 181 andthe NC terminal 182 first. At this time, the lower face 175 of theinsulating sheet 184 is engaged with the groove 185 of the connectionmember 183. Next, the capacitor device 102 under the above state isinserted from the space at the lower face 175 into the region formedaround the cooling fin 174. The terminal unit that includes the PCterminal 181, the NC terminal 182, and the connection member 183, isthen sandwiched between the lead terminals 133, 143 from both sides inthe lateral direction. At this time, the lateral outer faces of the PCterminal 181 abut the first principal planes of each lead terminal 133,and the lateral outer faces of the NC terminal 182 abut the secondprincipal planes of each lead terminal 143. That is to say, theterminals of the same polarity are interconnected. During the aboveinsertion, the protrusion 186 of the connection member 183 is engagedwith the groove 153 of the second molded section 152. In addition,longitudinal positions of the screw holes 135, 187 and thenut-containing portion 119 agree with those of the screw holes 146, 188and the other nut-containing portion 119.

The section where the protrusion 186 of the connection member 183 isengaged with the groove 153 of the second molded section 152 is providedto ensure a creeping distance at an interface of the connecting portionbetween the connection member 183 and the electric circuit device 110and thus to prevent electrical discharge. Also, the section where thegroove 185 in the connection member 183 and the insulating sheet 184become engaged with each other is provided to ensure a creeping distanceat an interface of the connecting portion between the connection member183 and the insulating sheet 184 and thus to prevent electricaldischarge.

Next, the screw 109 is inserted into the screw hole 135, 187 at one sidein the lateral direction via the screw insertion hole 179 in the sidewall of the cooling fin 174. Thus, the screw 109 is threadably engagedwith the nut 189 contained in the nut-containing portion 119 at one sidein the lateral direction. The screw 109 is also inserted into the screwhole 146, 188 at the other side in the lateral direction and threadablyengaged with the nut 189 contained in the nut-containing portion 119 atthe other side in the lateral direction. The screw insertion hole 179provided at where it matches the screw hole 135, 187 and thenut-containing portion 119 associated therewith is also provided atwhere it matches the screw hole 146, 188 and the nut-containing portion119 associated therewith. Also, the screw insertion hole 179 is largerthan those screw holes in diameter. The above connecting operations cantherefore be performed easily. Hence, the capacitor device 102 and thesemiconductor module 101 can be electrically connected.

According to the present embodiment, the PC terminal 181 and the NCterminal 182 are opposed to each other in parallel, so when a positivecurrent flows through the PC terminal 181 and a negative current equalto the positive current in magnitude and opposite in direction flowsthrough the NC terminal 182, the magnetic field generated by thepositive current can be offset by the magnetic field generated by thenegative current. Thus, according to the present embodiment, themagnetic field offset effect makes it possible to reduce the lineinductance developed between the PC terminal 181 and the NC terminal182. That is to say, according to the present embodiment, the lineinductance shown in FIG. 6 can be reduced.

According to the present embodiment, therefore, since the lineinductance 105 in the capacitor device 102 can be reduced, it ispossible to further reduce the switching loss of the IGBTs 111 and henceto further reduce the amount of heat generated by the IGBTs 111.According to the present embodiment, therefore, the electric circuitdevice 110 can be constructed using even smaller semiconductor chipsthat constitute the IGBTs 111. Thus, according to the presentembodiment, the electric circuit device 110 can be miniaturized and thesemiconductor module 101 in which to mount the electric circuit device110 can be correspondingly miniaturized.

The circuit board unit 190 includes a control circuit board 191 and aplurality of electronic components mounted thereon.

The mounted electronic components are a microcomputer 192 thatconstitutes the foregoing control unit, a driver circuit (IC) 193 thatconstitutes the foregoing driver, and a current sensor 194 that detectsa supply current to the foregoing semiconductor module 101.

The control circuit board 191 is a rectangular flat plate, which ismounted on the base unit and collars of the heat release base 170 viaspacers 197. Also, the control circuit board 191 is fixed to thesurfaces of the base unit and collars of the heat release base 170 bythreadable engagement of screws 195 with screw holes 178.

Three rectangular through-holes 196 extending through in a verticaldirection of the control circuit board 191 are formed in line in alongitudinal direction thereof so that each through-hole 196 matches tothe mounting position of one electric circuit device 110. Thethrough-hole 196 has an appropriate size such that the control circuitboard 191, when mounted on the base unit and collars of the heat releasebase 170, fits onto the insert-molded electric circuit devices 110. Inthe present embodiment, the insert-molded electric circuit devices 110can thus be fixed using the control circuit board 191. That is to say,the control circuit board 191 is used as a fixing jig in the presentembodiment.

The microcomputer 192 is mounted at one side in a lateral direction ofthe through-holes 196 positioned centrally in the longitudinal directionof the control circuit board 191. The driver 193 is provided for eachupper arm and each lower arm. The driver 193 is therefore mounted on thecontrol circuit board 191 so as to be disposed at both sides in thelateral direction of each through-hole 196, and near the G-wires 160,162 and S-wires 161, 163 of each electric circuit device 110 (i.e., atboth sides in a longitudinal direction of the through-hole 196). Thecurrent sensor 194 is mounted centrally at the through-holes 196positioned at both longitudinal ends of the control circuit board 191(i.e., the sensor 194 is mounted at a position associated with the leadwire 122 of each electric circuit device 110). The lead wire 122 of theelectric circuit device 110, mounted at both longitudinal ends, extendsthrough a hollow section of the current sensor 194. The electric circuitdevice 110 and each electronic component are electrically interconnectedby a wiring pattern and other wiring members provided on the controlcircuit board 191. Connection between the electronic components is alsoestablished using the wiring pattern and other wiring members.

In the present embodiment, the microcomputer 192 and the driver circuit193 are mounted on the same board, but both may be mounted onindependent boards. In addition, while the control circuit board 191 inthe present embodiment is mounted on the heat release base 170 via thespacers 197, the board 191 may be mounted on the heat release base 170without using the spacers 197. In this case, since the control circuitboard 191 and the heat release base 170 are thermally connected, thecontrol circuit board 191 is expected to be cooled.

When the inverter 100 is assembled, each electric circuit device 110that has been assembled in the manner described above is firstinsert-molded onto each heat release base 170 and then mounted thereonto construct the semiconductor module 101. Next, as described above, thesemiconductor module 101 and the capacitor device 102 are electricallyconnected. Finally, the control circuit board 191 with mountedelectronic components is mounted on the heat release base 170, and thusthe inverter 100 is assembled.

As described above, according to the present embodiment, reduction inline inductance and the improvement of cooling performance by both-sidecooling can be achieved at the same time. According to the presentembodiment, it is thus possible to construct an electric circuit device110 using semiconductor chips smaller than conventional ones, and henceto make the electric circuit device 110 more compact than conventionalones. The present embodiment, therefore, realizes the miniaturization ofthe semiconductor module 101 in which to mount the electric circuitdevice 110, and furthermore, the miniaturization of the inverter 100 inwhich to mount the semiconductor module 101 itself.

According to the present embodiment, since the electric circuit device110 is constructed for each arm, that is, on a two-in-one scheme basis,the mounting space of the electric circuit devices 110 in thesemiconductor module 101 can also be reduced to achieve furtherminiaturization of the semiconductor module 101 and the inverter 100.

In the present embodiment, a flow direction of the coolant in thesemiconductor module 101, input and output directions of current in theelectric circuit device 110, and a heat release direction of thesemiconductor chips in the electric circuit device 110 are in anorthogonal relationship to one another.

Second Embodiment

A second embodiment of the present invention will be described per FIG.21.

The present embodiment, an improvement of the first embodiment, is anexample of transposing the configurations of the P-electrode 130 andN-electrode 140 of the first embodiment. The present (second) embodimentdiffers from the first embodiment in three respects. One is that aconfiguration of a first bend 136 is added to the P-electrode 130(however, the first bend 136 differs from the first bend 144 of thefirst embodiment in terms of position and is opposite in extendingdirection of a conductor). One is that the configuration of the leadwire 132 is replaced with a configuration of a lead wire 142 in thefirst embodiment (however, the lead wire 132 is opposite to the leadwire 142 of the first embodiment in terms of extending direction of aconductor). One is that since the first bend is removed from theN-electrode 140, the configuration of the lead wire 142 is replaced witha configuration of a lead wire 132 in the first embodiment (however, thelead wire 142 is opposite to the lead wire 132 of the first embodimentin terms of extending direction of a conductor). Other elements are thesame as those of the first embodiment in terms of configuration, so thesame reference number or symbol is assigned to the same element,description of which is omitted.

In the present embodiment described above, as in the first embodiment,reduction in line inductance and the improvement of cooling performanceby both-side cooling of semiconductor chips can be achieved at the sametime and electric circuit devices 110 can be miniaturized.

Third Embodiment

A third embodiment of the present invention will be described per FIG.22.

The present embodiment, an application of the first embodiment, is anexample of connecting arms' IGBTs 111 and diodes 112 in two lines inparallel. In the present (third) embodiment, the same pair of chips asthat of HI and HD chips juxtaposed in a short-side direction arejuxtaposed in a long-side direction, and the same pair of chips as thatof LI and LD chips juxtaposed in a short-side direction are juxtaposedin a long-side direction. Along with these, the number of G-wires 160,162 and S-wires 161, 163 is also correspondingly increased. In thepresent embodiment, various electrodes have areas larger than those ofthe electrodes in the first embodiment. Other elements are the same asthose of the first embodiment in terms of configuration, so the samereference number or symbol is assigned to the same element, descriptionof which is omitted.

In the present embodiment described above, as in the first embodiment,reduction in line inductance and the improvement of cooling performanceby both-side cooling of semiconductor chips can be achieved at the sametime and electric circuit devices 110 can be miniaturized.

According to the present embodiment, since the semiconductor chips areconnected in two lines in parallel, each electric circuit device 110 canbe increased in current density. In the same perspective, the number ofparallel connection lines of the semiconductor chips can be increased tothree and further to four, so the electric circuit device 110 can befurther increased in current density.

Fourth Embodiment

A fourth embodiment of the present invention will be described per FIG.23.

The present embodiment, a modification of the first embodiment, is anexample in which the HI and HD chips juxtaposed in the short-sidedirection in the first embodiment and the LI and LD chips alsojuxtaposed in the short-side direction in the first embodiment are eachjuxtaposed in a long-side direction. In the present (fourth) embodiment,the HD and LD chips are arranged more internally to an electric circuitdevice than the HI and LI chips. In the present embodiment, variouselectrodes have areas smaller than those of the electrodes in the firstembodiment. Other elements are the same as those of the first embodimentin terms of configuration, so the same reference number or symbol isassigned to the same element, description of which is omitted.

In the present embodiment described above, as in the first embodiment,reduction in line inductance and the improvement of cooling performanceby both-side cooling of semiconductor chips can be achieved at the sametime and electric circuit devices 110 can be miniaturized.

According to the present embodiment, connecting the semiconductor chipsin two, three, or four lines in parallel, as in the third embodiment,makes it possible to increase each electric circuit device 110 incurrent density.

Fifth Embodiment

A fifth embodiment of the present invention will be described per FIGS.24 to 26.

The present embodiment, another application of the first embodiment, isan example in which the semiconductor module 101 and capacitor device102 in the first embodiment are connected together to form a basic unit210 and multiple basic units 210 are arranged next to one another in ashort-side direction. In the present (fifth) embodiment, three basicunits 210 are juxtaposed for mutual contact between cooling fins 174 andare stored in a main unit casing 220. Heat release bases 170 have nocollars and are of lateral thickness smaller than in the firstembodiment. C-blocks 180 also are of lateral thickness smaller than inthe first embodiment. Other elements are the same as those of the firstembodiment in terms of configuration, so the same reference number orsymbol is assigned to the same element, description of which is omitted.

A unit terminal 240 is electrically connected to the C-block 180 (PCterminal and NC terminal) of each basic unit 210. The unit terminal 240protrudes in a longitudinal direction from a region formed between thecooling fins 174 of any two basic units 210. The unit terminal 240includes a positive-polarity terminal 241, a negative-polarity terminal242, and an insulating sheet 243. The positive-polarity terminal 241 andthe negative-polarity terminal 242 are stacked vertically with theinsulating sheet 243 sandwiched between both, and are opposed inproximity and in parallel to each other. After front ends of thepositive-polarity terminal 241 and the negative-polarity terminal 242have protruded longitudinally from the region formed between the coolingfins 174, one of the front ends is bent at right angles outward in avertical direction and then extends straightly, whereas the other frontend is bent at right angles outward in a vertical direction and thenextends straightly. A screw hole is formed at the respective front endsof the positive-polarity terminal 241 and the negative-polarity terminal242.

The unit terminals 240 are integratedly interconnected via an integratedterminal 230. The integrated terminal 230 includes a positive-polarityelectrode 234, a negative-polarity electrode 236, and an insulatingsheet 233. The positive-polarity electrode 234 and the negative-polarityelectrode 236 are stacked vertically with the insulating sheet 233sandwiched between both, and are opposed in proximity and in parallel toeach other. Also, the positive-polarity electrode 234 and thenegative-polarity electrode 236 both have a rectangular flat-platelaminate. A terminal 231 extending straightly towards one longitudinalside of the flat-plate laminate of the positive-polarity electrode 234is formed at the particular longitudinal side, and three terminals 235each bent at right angles towards one vertical side from the otherlongitudinal side and extending straightly is formed at the particularother longitudinal side. A terminal 232 extending straightly towards onelongitudinal side of the flat-plate laminate of the negative-polarityelectrode 236 is formed at the particular longitudinal side, and threeterminals 237 each bent at right angles towards the other vertical sidefrom the other longitudinal side and extending straightly is formed atthe particular other longitudinal side. A screw hole is formed at therespective front ends of the terminals 231, 233 and terminals 235, 237.

The front end of the positive-polarity terminal 241 of the unit terminal240 and a terminal 235 abut each other in an opposed condition and arescrew-connected. The front end of the negative-polarity terminal 242 ofthe unit terminal 240 and a terminal 237 abut each other in an opposedcondition and are screw-connected. Thus, the C-blocks (PC terminals andNC terminals) of the same polarity are integratedly connected. Theintegrated electrode 230 is constructed so that current paths from theterminals 231, 232 to the associated C-blocks 180 are equal in length.

The lead terminals 123 of each basic unit 210 are also integratedlyconnected for equal length of current paths on a phase-by-phase basis.

Since screw holes 221 are formed in the main unit casing 220, thecontrol circuit board with mounted electronic components can be mounted,as in the first embodiment.

The electric circuit devices 110 in the first embodiment may be replacedwith those of any one of the second to fourth embodiments.

According to the present embodiment described above, since the multiplebasic units 210 are integratedly connected using the integrated terminal230, reduction in line inductance and the improvement of coolingperformance by both-side cooling of the semiconductor chips can besimultaneously achieved, as in the first embodiment. In addition, theelectric circuit devices 110 can be made more compact and thus aninverter 100 of a larger capacity can be realized.

According to the present embodiment, since the integrated terminal 230is constructed for equal length of the current paths extending from theterminals 231, 232 to the C-blocks 180, line inductance from the unitterminal 240 to the electric circuit device 110 can be well matchedbetween the basic units 210.

Sixth Embodiment

A sixth embodiment of the present invention will be described based onFIGS. 27 and 28.

The present embodiment, a modification of the fifth embodiment, is anexample in which the unit terminal 240 is provided at the bottom of theC-block 180. For this reason, an opening 113 for exposing the unitterminal 240 is formed centrally at the bottom of the main unit casing220 in a lateral direction thereof. The unit terminal 240 is essentiallyof the same configuration as in the fifth embodiment, except that theunit terminal 240 is rotationally moved through 90 degrees in a verticaldirection of the terminal from a longitudinal direction thereof. Theintegrated terminal 230 also has the same configuration as in the fifthembodiment.

According to the present embodiment described above, since the multiplebasic units 210 are integratedly connected using the integrated terminal230, reduction in line inductance and the improvement of coolingperformance by both-side cooling of the semiconductor chips can besimultaneously achieved, as in the first embodiment. In addition, theelectric circuit devices 110 can be made more compact and thus aninverter 100 of a larger capacity can be realized.

According to the present embodiment, since the integrated terminal 230is constructed for equal length of the current paths extending from theterminals 231, 232 to the C-blocks 180, line inductance from the unitterminal 240 to the electric circuit device 110 can be well matchedbetween the basic units 210.

Seventh Embodiment

A seventh embodiment of the present invention will be described based onFIGS. 29 to 33.

The present embodiment, another modification of the first embodiment, isan example in which the screw holes in the lead terminals 133, 143 areformed as insertion portions 137, 147 for welded bolts. For this reason,the C-block 180 has terminals stacked in a longitudinal direction withan insulating sheet 260 sandwiched between an PC terminal 261 and an NCterminal 262. The PC terminal 261 and the NC terminal 262 have thewelded bolts instead of screw holes. A concave groove 154 for engagingan insulating sheet 264 therewith is formed at the bottom of the secondmolded section 152. Clearance 260 between the lead terminals 133, 143 issmaller than in the first embodiment.

The groove 154 is provided to ensure a creeping distance at an interfaceof the connecting portion between the insulating sheet 264 and theelectric circuit device 100 and thus to prevent electrical discharge.

In the present embodiment, the lead terminal 133, 143 is used to engagethe welded-bolt insertion portion 137, 147 and the welded bolt 263 suchthat the terminals of the C-block 180 are sandwiched from both sides inthe lateral direction. Also, a nut 264 is threadably engaged with thewelded bolt 263 in that state. Thus, the lead terminal 133 and the leadterminal 143 abut on the P terminal 261 and the NC terminal 262,respectively, and are linked together.

According to the present embodiment described above, the positive sideand negative side at the connection between the lead terminal 133, 143and an associated terminal of the C-block 180 can be made closer to eachother than in the first embodiment. Also, currents that flow through thepositive and negative sides can be completely opposed with equalmagnitude and opposite directionality. According to the presentembodiment, therefore, line inductance can be reduced more significantlythan in the first embodiment.

Eighth Embodiment

An eighth embodiment of the present invention will be described perFIGS. 34 and 35.

The present embodiment, yet another modification of the firstembodiment, is an example in which both-side cooling and line inductancereduction can be achieved at the same time without using the first bend144 of the N-electrode 140. For this reason, the present embodimentprovides metallic spacers 270 and 271 of a rectangular flat-plate shapethat are made of copper excellent in electrical conductivity and inthermal conductivity. The metallic spacer 270 is connected between thechip surface at the emitter electrode side of an HI chip, the chipsurface at the anodic electrode side of an HD chip, and the mountingsurface of the heat-releasing section 121, and the metallic spacer 271is mounted on the heat release plane of the heat-releasing section 141.

The heat-releasing section 141 is disposed on the same plane as that ofthe lead wire 142. Therefore, the heat release plane of theheat-releasing section 141 cannot be exposed at the second principalplane of the first molded section 151. Instead, a second principal planeof the metallic spacer 271 serves as the heat release plane of theheat-releasing section 141 and is exposed at the surface of the secondprincipal plane of the first molded section 151.

The metallic spacer 270 may be disposed integrally with the M-electrode120.

In the present embodiment described above, as in the first embodiment,reduction in line inductance and the improvement of cooling performanceby both-side cooling of semiconductor chips can be achieved at the sametime and electric circuit devices 110 can be miniaturized.

According to the present embodiment, connecting the semiconductor chipsin two, three, or four lines in parallel, as in the third embodiment,makes it possible to increase each electric circuit device 110 incurrent density.

1. An electric power converter comprising: a plurality of electriccircuit devices respectively having a semiconductor chip for convertingdirect current to alternating current and a lead terminal fortransferring said direct current to said semiconductor chip; a capacitorblock having a capacitor element for smoothing said direct current and acapacitor terminal for transferring said direct current to said leadterminal; and a heat release base having a flow channel for carrying acooling medium; wherein said heat release base comprises a plurality ofelectric circuit device insertion sections and a cooling fin for holdingsaid capacitor block; said electric circuit devices respectively have afirst heat releasing section and a second heat releasing section facingsaid first heat releasing section through said semiconductor chip; saidheat release base fixes said electric circuit devices in said electriccircuit device insertion sections so that said first heat releasingsection and said second heat releasing section are disposed between saidflow channel; and said capacitor block is fixed by said cooling fin sothat said capacitor terminal directly connects to said lead terminal. 2.The electric power converter according to claim 1, wherein saidcapacitor terminal is one of a positive capacitor terminal and anegative capacitor terminal; said capacitor block has a casing forholding said capacitor element and a insulating sheet disposed betweensaid positive capacitor terminal and said negative capacitor terminal;and said positive capacitor terminal and said negative capacitorterminal protrude from said casing with said insulating sheet positionedtherebetween.
 3. The electric power converter according to claim 2,wherein said lead terminal is one of a positive lead terminal and anegative lead terminal; and an end part of said positive capacitorterminal and an end part of said negative capacitor terminal extend to aspace between said positive lead terminal and said negative leadterminal.
 4. The electric power converter according to claim 1, furthercomprising: a control circuit board, which has electronic components forcontrolling switching timing of said semiconductor chip; wherein saidcontrol circuit board is fixed by said heat release base.
 5. Theelectric power converter according to claim 4, wherein said controlcircuit board has a plurality of through-holes; and each of said eachthrough-holes faces one of said electric circuit device insertionsections and fixes one of said electric circuit devices.
 6. The electricpower converter according to claim 4, wherein said control circuit boardfaces said capacitor block through said electric circuit devices andsaid flow channel.
 7. The electric power converter according to claim 6,further comprising: a plurality of current sensors for detecting saidalternating current; wherein said current sensors are disposed on saidcircuit board; each of said electric circuit devices has a lead wire foroutputting said alternating current; each of said lead wires extends toone of said current sensors; and said lead terminal extends to saidcapacitor block.